Kalta will have player hosted Gyms and Elite 4. You can gain rewards for beating each gym adn each elite 4 member. Once the player beats all 8 Gyms and Elite 4 they will get a special reward and be put in the hall of fame.
In Kalta you're able to breed, fly and ride your pokemon, legendary pokemon are able to spawn and When we reach certain amounts of players there will be special events (Drop parties, legendary drops etc.). Voting for the server will give you some nice rewards!